Traditionally, radio frequency (RF) switches at millimeter-wave (mmWave) frequencies are fabricated using GaAs metal epitaxial semiconductor field effect transistors (MESFETs) or PIN diodes, either as discrete components, or on a GaAs integrated circuit. But GaAs and other III-V semiconductor materials are more expensive than silicon and typically require higher supply voltages and consume more power then Si integrated circuits (ICs). Thus, it is desirable to produce an RF switch in Si with insertion loss comparable to GaAs devices.
However, it is difficult to produce a low insertion loss switch for radio frequency (RF) signals, especially at millimeter-wave (mmWave) frequencies, in a silicon complementary metal-oxide-semiconductor (CMOS) process because the silicon FETs and the silicon substrate itself are very lossy. Similar problems are associated with a silicon BiCMOS process in which CMOS devices and bipolar junction transistors (BJT) are integrated in a single device. For example, in the arrangement disclosed by U.S. Pat. No. 7,123,898, the disclosure of which is incorporated herein, elaborate circuits are used for biasing the gates of the field effect transistors (FETs) in a single-pull double-throw (SPDT) switch, but no arrangements are made for minimizing substrate-related losses.